<!DOCTYPE html>



  


<html class="theme-next pisces use-motion" lang="zh-Hans">
<head><meta name="generator" content="Hexo 3.8.0">
  <meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">
<meta name="theme-color" content="#222">

<script>
    (function () {
        if ('') {
            if (prompt('请输入文章密码') !== '') {
                alert('密码错误！');
                if (history.length === 1) {
                    location.replace("https://xczhello.gitee.io/"); // 这里替换成你的首页
                } else {
                    history.back();
                }
            }
        }
    })();
</script>








<meta http-equiv="Cache-Control" content="no-transform">
<meta http-equiv="Cache-Control" content="no-siteapp">
















  
  
  <link href="/lib/fancybox/source/jquery.fancybox.css?v=2.1.5" rel="stylesheet" type="text/css">







<link href="/lib/font-awesome/css/font-awesome.min.css?v=4.6.2" rel="stylesheet" type="text/css">

<link href="/css/main.css?v=5.1.4" rel="stylesheet" type="text/css">


  <link rel="apple-touch-icon" sizes="180x180" href="/images/favicon.jpg?v=5.1.4">


  <link rel="icon" type="image/png" sizes="32x32" href="/images/favicon.jpg?v=5.1.4">


  <link rel="icon" type="image/png" sizes="16x16" href="/images/favicon.jpg?v=5.1.4">






  <meta name="keywords" content="Hexo, NexT">










<meta name="description" content="1. MVVM 和 Vue 如何理解 MVVM如何实现 MVVM是否解读过 vue 的源码  1.1. 说一下使用 jQuery 和使用框架的区别1.1.1. jQuery 实现 todo-list123456789101112131415161718192021&amp;lt;div&amp;gt;  &amp;lt;input type=&quot;text&quot; name=&quot;&quot; id=&quot;txt-title&quot; /&amp;gt;  &amp;lt">
<meta property="og:type" content="article">
<meta property="og:title" content="我的博客">
<meta property="og:url" content="https://xczhello.gitee.io/uncategorized/imooc-frontend-interview/JavaScript高级面试/5. MVVM和Vue.html/index.html">
<meta property="og:site_name" content="我的博客">
<meta property="og:description" content="1. MVVM 和 Vue 如何理解 MVVM如何实现 MVVM是否解读过 vue 的源码  1.1. 说一下使用 jQuery 和使用框架的区别1.1.1. jQuery 实现 todo-list123456789101112131415161718192021&amp;lt;div&amp;gt;  &amp;lt;input type=&quot;text&quot; name=&quot;&quot; id=&quot;txt-title&quot; /&amp;gt;  &amp;lt">
<meta property="og:locale" content="zh-Hans">
<meta property="og:image" content="https://xczhello.gitee.io/uncategorized/imooc-frontend-interview/JavaScript高级面试/images/code.render.png">
<meta property="og:image" content="https://xczhello.gitee.io/uncategorized/imooc-frontend-interview/JavaScript高级面试/images/render.png">
<meta property="og:updated_time" content="2019-01-05T13:47:03.000Z">
<meta name="twitter:card" content="summary">
<meta name="twitter:title" content="我的博客">
<meta name="twitter:description" content="1. MVVM 和 Vue 如何理解 MVVM如何实现 MVVM是否解读过 vue 的源码  1.1. 说一下使用 jQuery 和使用框架的区别1.1.1. jQuery 实现 todo-list123456789101112131415161718192021&amp;lt;div&amp;gt;  &amp;lt;input type=&quot;text&quot; name=&quot;&quot; id=&quot;txt-title&quot; /&amp;gt;  &amp;lt">
<meta name="twitter:image" content="https://xczhello.gitee.io/uncategorized/imooc-frontend-interview/JavaScript高级面试/images/code.render.png">



<script type="text/javascript" id="hexo.configurations">
  var NexT = window.NexT || {};
  var CONFIG = {
    root: '/',
    scheme: 'Pisces',
    version: '5.1.4',
    sidebar: {"position":"left","display":"post","offset":12,"b2t":true,"scrollpercent":true,"onmobile":false},
    fancybox: true,
    tabs: true,
    motion: {"enable":true,"async":false,"transition":{"post_block":"fadeIn","post_header":"slideDownIn","post_body":"slideDownIn","coll_header":"slideLeftIn","sidebar":"slideUpIn"}},
    duoshuo: {
      userId: '0',
      author: '博主'
    },
    algolia: {
      applicationID: '',
      apiKey: '',
      indexName: '',
      hits: {"per_page":10},
      labels: {"input_placeholder":"Search for Posts","hits_empty":"We didn't find any results for the search: ${query}","hits_stats":"${hits} results found in ${time} ms"}
    }
  };
</script>



  <link rel="canonical" href="https://xczhello.gitee.io/uncategorized/imooc-frontend-interview/JavaScript高级面试/5. MVVM和Vue.html/">





  <title> | 我的博客</title>
  








</head>

<body itemscope="" itemtype="http://schema.org/WebPage" lang="zh-Hans">

  
  
    
  

  <div class="container sidebar-position-left page-post-detail">
    <div class="headband"></div>

    <a href="https://github.com/Jem826" class="github-corner" aria-label="View source on GitHub"><svg width="80" height="80" viewbox="0 0 250 250" style="fill:#151513; color:#fff; position: absolute; top: 0; border: 0; right: 0;" aria-hidden="true"><path d="M0,0 L115,115 L130,115 L142,142 L250,250 L250,0 Z"/><path d="M128.3,109.0 C113.8,99.7 119.0,89.6 119.0,89.6 C122.0,82.7 120.5,78.6 120.5,78.6 C119.2,72.0 123.4,76.3 123.4,76.3 C127.3,80.9 125.5,87.3 125.5,87.3 C122.9,97.6 130.6,101.9 134.4,103.2" fill="currentColor" style="transform-origin: 130px 106px;" class="octo-arm"/><path d="M115.0,115.0 C114.9,115.1 118.7,116.5 119.8,115.4 L133.7,101.6 C136.9,99.2 139.9,98.4 142.2,98.6 C133.8,88.0 127.5,74.4 143.8,58.0 C148.5,53.4 154.0,51.2 159.7,51.0 C160.3,49.4 163.2,43.6 171.4,40.1 C171.4,40.1 176.1,42.5 178.8,56.2 C183.1,58.6 187.2,61.8 190.9,65.4 C194.5,69.0 197.7,73.2 200.1,77.6 C213.8,80.2 216.3,84.9 216.3,84.9 C212.7,93.1 206.9,96.0 205.4,96.6 C205.1,102.4 203.0,107.8 198.3,112.5 C181.9,128.9 168.3,122.5 157.7,114.1 C157.9,116.9 156.7,120.9 152.7,124.9 L141.0,136.5 C139.8,137.7 141.6,141.9 141.8,141.8 Z" fill="currentColor" class="octo-body"/></svg></a><style>.github-corner:hover .octo-arm{animation:octocat-wave 560ms ease-in-out}@keyframes octocat-wave{0%,100%{transform:rotate(0)}20%,60%{transform:rotate(-25deg)}40%,80%{transform:rotate(10deg)}}@media (max-width:500px){.github-corner:hover .octo-arm{animation:none}.github-corner .octo-arm{animation:octocat-wave 560ms ease-in-out}}</style>

    <header id="header" class="header" itemscope="" itemtype="http://schema.org/WPHeader">
      <div class="header-inner"><div class="site-brand-wrapper">
  <div class="site-meta ">
    

    <div class="custom-logo-site-title">
      <a href="/" class="brand" rel="start">
        <span class="logo-line-before"><i></i></span>
        <span class="site-title">我的博客</span>
        <span class="logo-line-after"><i></i></span>
      </a>
    </div>
      
        <p class="site-subtitle"></p>
      
  </div>

  <div class="site-nav-toggle">
    <button>
      <span class="btn-bar"></span>
      <span class="btn-bar"></span>
      <span class="btn-bar"></span>
    </button>
  </div>
</div>

<nav class="site-nav">
  

  
    <ul id="menu" class="menu">
      
        
        <li class="menu-item menu-item-home">
          <a href="/" rel="section">
            
              <i class="menu-item-icon fa fa-fw fa-home"></i> <br>
            
            首页
          </a>
        </li>
      
        
        <li class="menu-item menu-item-tags">
          <a href="/tags/" rel="section">
            
              <i class="menu-item-icon fa fa-fw fa-tags"></i> <br>
            
            标签
          </a>
        </li>
      
        
        <li class="menu-item menu-item-categories">
          <a href="/categories/" rel="section">
            
              <i class="menu-item-icon fa fa-fw fa-th"></i> <br>
            
            分类
          </a>
        </li>
      
        
        <li class="menu-item menu-item-archives">
          <a href="/archives/" rel="section">
            
              <i class="menu-item-icon fa fa-fw fa-archive"></i> <br>
            
            归档
          </a>
        </li>
      
        
        <li class="menu-item menu-item-linkfriends">
          <a href="/linkfriends/" rel="section">
            
              <i class="menu-item-icon fa fa-fw fa-link"></i> <br>
            
            友情链接
          </a>
        </li>
      
        
        <li class="menu-item menu-item-hot">
          <a href="/hot/" rel="section">
            
              <i class="menu-item-icon fa fa-fw fa-fire"></i> <br>
            
            热点关注
          </a>
        </li>
      
        
        <li class="menu-item menu-item-about">
          <a href="/about/" rel="section">
            
              <i class="menu-item-icon fa fa-fw fa-user"></i> <br>
            
            关于
          </a>
        </li>
      

      
        <li class="menu-item menu-item-search">
          
            <a href="javascript:;" class="popup-trigger">
          
            
              <i class="menu-item-icon fa fa-search fa-fw"></i> <br>
            
            搜索
          </a>
        </li>
      
    </ul>
  

  
    <div class="site-search">
      
  <div class="popup search-popup local-search-popup">
  <div class="local-search-header clearfix">
    <span class="search-icon">
      <i class="fa fa-search"></i>
    </span>
    <span class="popup-btn-close">
      <i class="fa fa-times-circle"></i>
    </span>
    <div class="local-search-input-wrapper">
      <input autocomplete="off" placeholder="搜索..." spellcheck="false" type="text" id="local-search-input">
    </div>
  </div>
  <div id="local-search-result"></div>
</div>



    </div>
  
</nav>



 </div>
    </header>

    <main id="main" class="main">
      <div class="main-inner">
        <div class="content-wrap">
          <div id="content" class="content">
            

  <div id="posts" class="posts-expand">
    

  

  
  
  

  <article class="post post-type-normal" itemscope="" itemtype="http://schema.org/Article">
  
  
  
  <div class="post-block">
    <link itemprop="mainEntityOfPage" href="https://xczhello.gitee.io/uncategorized/imooc-frontend-interview/JavaScript高级面试/5. MVVM和Vue.html/">

    <span hidden itemprop="author" itemscope="" itemtype="http://schema.org/Person">
      <meta itemprop="name" content="Yomi">
      <meta itemprop="description" content="">
      <meta itemprop="image" content="/images/head.jpg">
    </span>

    <span hidden itemprop="publisher" itemscope="" itemtype="http://schema.org/Organization">
      <meta itemprop="name" content="我的博客">
    </span>

    
      <header class="post-header">

        
        
          <h1 class="post-title" itemprop="name headline"></h1>
        

        <div class="post-meta">
          <span class="post-time">
            
              <span class="post-meta-item-icon">
                <i class="fa fa-calendar-o"></i>
              </span>
              
                <span class="post-meta-item-text">发表于</span>
              
              <time title="创建于" itemprop="dateCreated datePublished" datetime="2019-03-06T17:48:34+08:00">
                2019-03-06
              </time>
            

            

            

            
          </span>

          

          

          
            
              <span class="post-comments-count">
                <span class="post-meta-divider">|</span>
                <span class="post-meta-item-icon">
                  <i class="fa fa-comment-o"></i>
                </span>
                <a href="/uncategorized/imooc-frontend-interview/JavaScript高级面试/5. MVVM和Vue.html/#comments" itemprop="discussionUrl">
                  <span class="post-comments-count disqus-comment-count" data-disqus-identifier="uncategorized/imooc-frontend-interview/JavaScript高级面试/5. MVVM和Vue.html/" itemprop="commentCount"></span>
                </a>
              </span>
            
          

          
          

          
            <span class="post-meta-divider">|</span>
            <span class="page-pv"><i class="fa fa-file-o"></i> 阅读数
            <span class="busuanzi-value" id="busuanzi_value_page_pv"></span>
            </span>
          

          
            <div class="post-wordcount">
              
                
                <span class="post-meta-item-icon">
                  <i class="fa fa-file-word-o"></i>
                </span>
                
                  <span class="post-meta-item-text">字数统计&#58;</span>
                
                <span title="字数统计">
                  2.4k字
                </span>
              

              
                <span class="post-meta-divider">|</span>
              

              
                <span class="post-meta-item-icon">
                  <i class="fa fa-clock-o"></i>
                </span>
                
                  <span class="post-meta-item-text">阅读时长 &asymp;</span>
                
                <span title="阅读时长">
                  11分钟
                </span>
              
            </div>
          

          

        </div>
      </header>
    

    
    
    
    <div class="post-body" itemprop="articleBody">

      
      

      
        <h1 id="1-MVVM-和-Vue"><a href="#1-MVVM-和-Vue" class="headerlink" title="1. MVVM 和 Vue"></a>1. MVVM 和 Vue</h1><blockquote>
<p>如何理解 MVVM<br>如何实现 MVVM<br>是否解读过 vue 的源码</p>
</blockquote>
<h2 id="1-1-说一下使用-jQuery-和使用框架的区别"><a href="#1-1-说一下使用-jQuery-和使用框架的区别" class="headerlink" title="1.1. 说一下使用 jQuery 和使用框架的区别"></a>1.1. 说一下使用 jQuery 和使用框架的区别</h2><h3 id="1-1-1-jQuery-实现-todo-list"><a href="#1-1-1-jQuery-实现-todo-list" class="headerlink" title="1.1.1. jQuery 实现 todo-list"></a>1.1.1. jQuery 实现 todo-list</h3><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">input</span> <span class="attr">type</span>=<span class="string">"text"</span> <span class="attr">name</span>=<span class="string">""</span> <span class="attr">id</span>=<span class="string">"txt-title"</span> /&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">button</span> <span class="attr">id</span>=<span class="string">"btn-submit"</span>&gt;</span>submit<span class="tag">&lt;/<span class="name">button</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;<span class="name">div</span>&gt;</span><span class="tag">&lt;<span class="name">ul</span> <span class="attr">id</span>=<span class="string">"ul-list"</span>&gt;</span><span class="tag">&lt;/<span class="name">ul</span>&gt;</span><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"></span><br><span class="line"><span class="tag">&lt;<span class="name">script</span> <span class="attr">src</span>=<span class="string">"https://cdn.bootcss.com/jquery/3.2.1/jquery.min.js"</span>&gt;</span><span class="undefined"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;<span class="name">script</span> <span class="attr">type</span>=<span class="string">"text/javascript"</span>&gt;</span><span class="undefined"></span></span><br><span class="line"><span class="javascript">  <span class="keyword">var</span> $txtTitle = $(<span class="string">'#txt-title'</span>)</span></span><br><span class="line"><span class="javascript">  <span class="keyword">var</span> $btnSubmit = $(<span class="string">'#btn-submit'</span>)</span></span><br><span class="line"><span class="javascript">  <span class="keyword">var</span> $ulList = $(<span class="string">'#ul-list'</span>)</span></span><br><span class="line"><span class="javascript">  $btnSubmit.click(<span class="function"><span class="keyword">function</span>(<span class="params"></span>) </span>&#123;</span></span><br><span class="line"><span class="javascript">    <span class="keyword">var</span> title = $txtTitle.val()</span></span><br><span class="line"><span class="javascript">    <span class="keyword">if</span> (!title) &#123;</span></span><br><span class="line"><span class="javascript">      <span class="keyword">return</span></span></span><br><span class="line"><span class="undefined">    &#125;</span></span><br><span class="line"><span class="javascript">    <span class="keyword">var</span> $li = $(<span class="string">'&lt;li&gt;'</span> + title + <span class="string">'&lt;/li&gt;'</span>)</span></span><br><span class="line"><span class="undefined">    $ulList.append($li)</span></span><br><span class="line"><span class="javascript">    $txtTitle.val(<span class="string">''</span>)</span></span><br><span class="line"><span class="undefined">  &#125;)</span></span><br><span class="line"><span class="undefined"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure>
<h3 id="1-1-2-vue-实现-todo-list"><a href="#1-1-2-vue-实现-todo-list" class="headerlink" title="1.1.2. vue 实现 todo-list"></a>1.1.2. vue 实现 todo-list</h3><figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span> <span class="attr">id</span>=<span class="string">"app"</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">div</span>&gt;</span><span class="tag">&lt;<span class="name">input</span> <span class="attr">v-model</span>=<span class="string">"title"</span> /&gt;</span> <span class="tag">&lt;<span class="name">button</span> <span class="attr">v-on:click</span>=<span class="string">"add"</span>&gt;</span>submit<span class="tag">&lt;/<span class="name">button</span>&gt;</span><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">div</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;<span class="name">ul</span>&gt;</span></span><br><span class="line">      <span class="tag">&lt;<span class="name">li</span> <span class="attr">v-for</span>=<span class="string">"item in list"</span>&gt;</span>&#123;&#123;item&#125;&#125;<span class="tag">&lt;/<span class="name">li</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;/<span class="name">ul</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"></span><br><span class="line"><span class="tag">&lt;<span class="name">script</span> <span class="attr">type</span>=<span class="string">"text/javascript"</span>&gt;</span><span class="undefined"></span></span><br><span class="line"><span class="javascript">  <span class="comment">// data 独立</span></span></span><br><span class="line"><span class="javascript">  <span class="keyword">var</span> data = &#123;</span></span><br><span class="line"><span class="javascript">    title: <span class="string">''</span>,</span></span><br><span class="line"><span class="undefined">    list: []</span></span><br><span class="line"><span class="undefined">  &#125;</span></span><br><span class="line"><span class="javascript">  <span class="comment">// 初始化 Vue 实例</span></span></span><br><span class="line"><span class="javascript">  <span class="keyword">var</span> vm = <span class="keyword">new</span> Vue(&#123;</span></span><br><span class="line"><span class="javascript">    el: <span class="string">'#app'</span>,</span></span><br><span class="line"><span class="undefined">    data: data,</span></span><br><span class="line"><span class="undefined">    methods: &#123;</span></span><br><span class="line"><span class="javascript">      add: <span class="function"><span class="keyword">function</span>(<span class="params"></span>) </span>&#123;</span></span><br><span class="line"><span class="javascript">        <span class="keyword">this</span>.list.push(<span class="keyword">this</span>.title)</span></span><br><span class="line"><span class="javascript">        <span class="keyword">this</span>.title = <span class="string">''</span></span></span><br><span class="line"><span class="undefined">      &#125;</span></span><br><span class="line"><span class="undefined">    &#125;</span></span><br><span class="line"><span class="undefined">  &#125;)</span></span><br><span class="line"><span class="undefined"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure>
<h3 id="1-1-3-jQuery-和框架的区别"><a href="#1-1-3-jQuery-和框架的区别" class="headerlink" title="1.1.3. jQuery 和框架的区别"></a>1.1.3. jQuery 和框架的区别</h3><ul>
<li><p>数据和视图的分离，解耦（开放封闭原则）</p>
</li>
<li><p>以数据驱动视图，只关心数据变化，DOM 操作被封装</p>
</li>
</ul>
<h2 id="1-2-说一下对-MVVM-的理解"><a href="#1-2-说一下对-MVVM-的理解" class="headerlink" title="1.2. 说一下对 MVVM 的理解"></a>1.2. 说一下对 MVVM 的理解</h2><ul>
<li>MVVM - Model View ViewModel</li>
<li>三者之间的联系</li>
<li>ViewModel 的理解，联系 View 和 Model</li>
</ul>
<h2 id="1-3-MVVM-框架的三大要素"><a href="#1-3-MVVM-框架的三大要素" class="headerlink" title="1.3. MVVM 框架的三大要素"></a>1.3. MVVM 框架的三大要素</h2><ul>
<li>响应式：vue 如何监听到 data 的每个属性变化？</li>
<li>模板引擎：vue 的模板如何被解析，指令如何处理？</li>
<li>渲染：vue 的模板如何被渲染成 html？以及渲染过程</li>
</ul>
<h2 id="1-4-vue-如何实现响应式"><a href="#1-4-vue-如何实现响应式" class="headerlink" title="1.4. vue 如何实现响应式"></a>1.4. vue 如何实现响应式</h2><h3 id="1-4-1-什么是响应式"><a href="#1-4-1-什么是响应式" class="headerlink" title="1.4.1. 什么是响应式"></a>1.4.1. 什么是响应式</h3><ul>
<li>修改 data 属性之后，vue 立刻监听到，立刻做出修改</li>
<li>data 属性被代理到 vm 上</li>
</ul>
<figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span> <span class="attr">id</span>=<span class="string">"app"</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">p</span>&gt;</span>&#123;&#123;name&#125;&#125;<span class="tag">&lt;/<span class="name">p</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">p</span>&gt;</span>&#123;&#123;age&#125;&#125;<span class="tag">&lt;/<span class="name">p</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;<span class="name">script</span> <span class="attr">src</span>=<span class="string">"https://unpkg.com/vue"</span>&gt;</span><span class="undefined"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;<span class="name">script</span> <span class="attr">type</span>=<span class="string">"text/javascript"</span>&gt;</span><span class="undefined"></span></span><br><span class="line"><span class="javascript">  <span class="keyword">var</span> vm = <span class="keyword">new</span> Vue(&#123;</span></span><br><span class="line"><span class="javascript">    el: <span class="string">'#app'</span>,</span></span><br><span class="line"><span class="undefined">    data: &#123;</span></span><br><span class="line"><span class="javascript">      name: <span class="string">'zhangsan'</span>,</span></span><br><span class="line"><span class="undefined">      age: 20</span></span><br><span class="line"><span class="undefined">    &#125;</span></span><br><span class="line"><span class="undefined">  &#125;)</span></span><br><span class="line"><span class="undefined"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure>
<h3 id="1-4-2-Object-defineProperty"><a href="#1-4-2-Object-defineProperty" class="headerlink" title="1.4.2. Object.defineProperty"></a>1.4.2. Object.defineProperty</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">var</span> obj = &#123;&#125;</span><br><span class="line"><span class="keyword">var</span> _name = <span class="string">'shangsan'</span></span><br><span class="line"><span class="built_in">Object</span>.defineProperty(obj, <span class="string">'name'</span>, &#123;</span><br><span class="line">    <span class="keyword">get</span>: function () &#123;</span><br><span class="line">        <span class="built_in">console</span>.log(<span class="string">'get'</span>, _name) <span class="comment">// 监听</span></span><br><span class="line">        <span class="keyword">return</span> _name</span><br><span class="line">    &#125;,</span><br><span class="line">    <span class="keyword">set</span>: function (newVal) &#123;</span><br><span class="line">        <span class="built_in">console</span>.log(<span class="string">'set'</span>, newVal)  <span class="comment">// 监听</span></span><br><span class="line">        _name = newVal</span><br><span class="line">    &#125;</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<h3 id="1-4-3-模拟"><a href="#1-4-3-模拟" class="headerlink" title="1.4.3. 模拟"></a>1.4.3. 模拟</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">var</span> vm = &#123;&#125;</span><br><span class="line"><span class="keyword">var</span> data = &#123;</span><br><span class="line">  name: <span class="string">'zhangsan'</span>,</span><br><span class="line">  age: <span class="number">20</span></span><br><span class="line">&#125;</span><br><span class="line"><span class="keyword">var</span> key, value</span><br><span class="line"><span class="keyword">for</span> (key <span class="keyword">in</span> data) &#123;</span><br><span class="line">  <span class="comment">// 命中闭包。新建一个函数保证key的独立作用域</span></span><br><span class="line">  ;(<span class="function"><span class="keyword">function</span>(<span class="params">key</span>) </span>&#123;</span><br><span class="line">    <span class="built_in">Object</span>.defineProperty(vm, key, &#123;</span><br><span class="line">      <span class="keyword">get</span>: function() &#123;</span><br><span class="line">        <span class="built_in">console</span>.log(<span class="string">'get'</span>, data[key]) <span class="comment">// 监听</span></span><br><span class="line">        <span class="keyword">return</span> data[key]</span><br><span class="line">      &#125;,</span><br><span class="line">      <span class="keyword">set</span>: function(newVal) &#123;</span><br><span class="line">        <span class="built_in">console</span>.log(<span class="string">'set'</span>, newVal) <span class="comment">// 监听</span></span><br><span class="line">        data[key] = newVal</span><br><span class="line">      &#125;</span><br><span class="line">    &#125;)</span><br><span class="line">  &#125;)(key)</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<h3 id="1-4-4-问题解答"><a href="#1-4-4-问题解答" class="headerlink" title="1.4.4. 问题解答"></a>1.4.4. 问题解答</h3><ul>
<li>关键是理解 Object.defineProperty</li>
<li>将 data 的属性代理到 vm 上</li>
</ul>
<h2 id="1-5-vue-如何解析模板"><a href="#1-5-vue-如何解析模板" class="headerlink" title="1.5. vue 如何解析模板"></a>1.5. vue 如何解析模板</h2><h3 id="1-5-1-模板是什么"><a href="#1-5-1-模板是什么" class="headerlink" title="1.5.1. 模板是什么"></a>1.5.1. 模板是什么</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br></pre></td><td class="code"><pre><span class="line">&lt;div id=<span class="string">"app"</span>&gt;</span><br><span class="line">  &lt;div&gt;</span><br><span class="line">    &lt;input v-model=<span class="string">"title"</span>&gt;</span><br><span class="line">    &lt;button v-on:click=<span class="string">"add"</span>&gt;submit&lt;<span class="regexp">/button&gt;</span></span><br><span class="line"><span class="regexp">  &lt;/</span>div&gt;</span><br><span class="line">  &lt;ul&gt;</span><br><span class="line">    &lt;li v-<span class="keyword">for</span>=<span class="string">"item in list"</span>&gt;&#123;&#123; item &#125;&#125;&lt;<span class="regexp">/li&gt;</span></span><br><span class="line"><span class="regexp">  &lt;/u</span>l&gt;</span><br><span class="line">&lt;<span class="regexp">/div&gt;</span></span><br></pre></td></tr></table></figure>
<ul>
<li>本质：对 vue 来说，模板本质就是一个字符串</li>
<li>有逻辑：如 v-if、v-for 等</li>
<li>与 html 格式很像，但有很大的区别</li>
<li>最终还要转换为 html 来显示</li>
<li>模板最终必须转换成 JS 代码，因为：<ul>
<li>有逻辑，必须用 JS 才能实现（图灵完备，判断循环递归等）</li>
<li>转换为 html 渲染页面，必须用 JS 才能实现</li>
<li>因此，模板最重要转换成一个 JS 函数（render 函数）</li>
</ul>
</li>
</ul>
<h3 id="1-5-2-render-函数"><a href="#1-5-2-render-函数" class="headerlink" title="1.5.2. render 函数"></a>1.5.2. render 函数</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br></pre></td><td class="code"><pre><span class="line">;<span class="xml"><span class="tag">&lt;<span class="name">div</span> <span class="attr">id</span>=<span class="string">"app"</span>&gt;</span></span></span><br><span class="line"><span class="xml">  <span class="tag">&lt;<span class="name">p</span>&gt;</span>&#123;&#123; price &#125;&#125;<span class="tag">&lt;/<span class="name">p</span>&gt;</span></span></span><br><span class="line"><span class="xml"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span></span><br><span class="line"></span><br><span class="line"><span class="keyword">with</span> (<span class="keyword">this</span>) &#123;</span><br><span class="line">  <span class="keyword">return</span> _c(</span><br><span class="line">    <span class="string">'div'</span>,</span><br><span class="line">    &#123;</span><br><span class="line">      attrs: &#123; <span class="attr">id</span>: <span class="string">'app'</span> &#125;</span><br><span class="line">    &#125;,</span><br><span class="line">    [_c(<span class="string">'p'</span>, [_v(_s(price))])]</span><br><span class="line">  )</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<ul>
<li>模板中所有的信息都包含在 render 函数中</li>
<li>this 即 vm</li>
<li>price 即 this.price 即 vm.price，即 data 中的 price</li>
<li>_c 即 this._c 即 vm.c</li>
</ul>
<figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span> <span class="attr">id</span>=<span class="string">"app"</span>&gt;</span><span class="tag">&lt;<span class="name">p</span>&gt;</span>&#123;&#123;price&#125;&#125;<span class="tag">&lt;/<span class="name">p</span>&gt;</span><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"></span><br><span class="line"><span class="tag">&lt;<span class="name">script</span>&gt;</span><span class="undefined"></span></span><br><span class="line"><span class="javascript">  <span class="keyword">var</span> vm = <span class="keyword">new</span> Vue(&#123;</span></span><br><span class="line"><span class="javascript">    el: <span class="string">'#app'</span>,</span></span><br><span class="line"><span class="undefined">    data: &#123;</span></span><br><span class="line"><span class="undefined">      price: 100</span></span><br><span class="line"><span class="undefined">    &#125;</span></span><br><span class="line"><span class="undefined">  &#125;)</span></span><br><span class="line"><span class="undefined"></span></span><br><span class="line"><span class="javascript">  <span class="comment">// 手写 render 函数</span></span></span><br><span class="line"><span class="javascript">  <span class="function"><span class="keyword">function</span> <span class="title">render</span>(<span class="params"></span>) </span>&#123;</span></span><br><span class="line"><span class="javascript">    <span class="keyword">with</span> (<span class="keyword">this</span>) &#123;</span></span><br><span class="line"><span class="javascript">      <span class="comment">// this 就是 vm</span></span></span><br><span class="line"><span class="javascript">      <span class="keyword">return</span> _c(</span></span><br><span class="line"><span class="javascript">        <span class="string">'div'</span>,</span></span><br><span class="line"><span class="undefined">        &#123;</span></span><br><span class="line"><span class="undefined">          attrs: &#123;</span></span><br><span class="line"><span class="javascript">            id: <span class="string">'app'</span></span></span><br><span class="line"><span class="undefined">          &#125;</span></span><br><span class="line"><span class="undefined">        &#125;,</span></span><br><span class="line"><span class="javascript">        [_c(<span class="string">'p'</span>, [_v(_s(price))])]</span></span><br><span class="line"><span class="undefined">      )</span></span><br><span class="line"><span class="undefined">    &#125;</span></span><br><span class="line"><span class="undefined">  &#125;</span></span><br><span class="line"><span class="undefined"></span></span><br><span class="line"><span class="javascript">  <span class="comment">// 相当于</span></span></span><br><span class="line"><span class="javascript">  <span class="function"><span class="keyword">function</span> <span class="title">render1</span>(<span class="params"></span>) </span>&#123;</span></span><br><span class="line"><span class="javascript">    <span class="keyword">return</span> vm._c(</span></span><br><span class="line"><span class="javascript">      <span class="string">'div'</span>,</span></span><br><span class="line"><span class="undefined">      &#123;</span></span><br><span class="line"><span class="undefined">        attrs: &#123;</span></span><br><span class="line"><span class="javascript">          id: <span class="string">'app'</span></span></span><br><span class="line"><span class="undefined">        &#125;</span></span><br><span class="line"><span class="undefined">      &#125;,</span></span><br><span class="line"><span class="javascript">      [vm._c(<span class="string">'p'</span>, [vm._v(vm._s(vm.price))])]</span></span><br><span class="line"><span class="undefined">    )</span></span><br><span class="line"><span class="undefined">  &#125;</span></span><br><span class="line"><span class="undefined"></span><span class="tag">&lt;/<span class="name">script</span>&gt;</span></span><br></pre></td></tr></table></figure>
<ul>
<li>从哪里可以看到 render 函数？</li>
<li>复杂一点的例子，render 函数是什么样子的？</li>
<li>v-if v-for v-on 都是怎么处理的？</li>
</ul>
<figure class="highlight html"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br></pre></td><td class="code"><pre><span class="line"><span class="tag">&lt;<span class="name">div</span> <span class="attr">id</span>=<span class="string">"app"</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">div</span>&gt;</span><span class="tag">&lt;<span class="name">input</span> <span class="attr">v-model</span>=<span class="string">"title"</span> /&gt;</span> <span class="tag">&lt;<span class="name">button</span> <span class="attr">v-on:click</span>=<span class="string">"add"</span>&gt;</span>submit<span class="tag">&lt;/<span class="name">button</span>&gt;</span><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;<span class="name">div</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;<span class="name">ul</span>&gt;</span></span><br><span class="line">      <span class="tag">&lt;<span class="name">li</span> <span class="attr">v-for</span>=<span class="string">"item in list"</span>&gt;</span>&#123;&#123;item&#125;&#125;<span class="tag">&lt;/<span class="name">li</span>&gt;</span></span><br><span class="line">    <span class="tag">&lt;/<span class="name">ul</span>&gt;</span></span><br><span class="line">  <span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br><span class="line"><span class="tag">&lt;/<span class="name">div</span>&gt;</span></span><br></pre></td></tr></table></figure>
<p>在 vue 源码中搜索<code>code.render</code>，然后加上<code>alert(code.render)</code></p>
<p><img src="/uncategorized/imooc-frontend-interview/JavaScript高级面试/5. MVVM和Vue.html/../images/code.render.png" alt="code.render"></p>
<p>复制浏览器中弹出的代码</p>
<p><img src="/uncategorized/imooc-frontend-interview/JavaScript高级面试/5. MVVM和Vue.html/../images/render.png" alt="render"></p>
<p>vue2.0 开始支持预编译，在开发环境下写模板经过编译打包之后放在生产环境下是 JS 代码</p>
<figure class="highlight js"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br><span class="line">18</span><br><span class="line">19</span><br><span class="line">20</span><br><span class="line">21</span><br><span class="line">22</span><br><span class="line">23</span><br><span class="line">24</span><br><span class="line">25</span><br><span class="line">26</span><br><span class="line">27</span><br><span class="line">28</span><br><span class="line">29</span><br><span class="line">30</span><br><span class="line">31</span><br><span class="line">32</span><br><span class="line">33</span><br><span class="line">34</span><br><span class="line">35</span><br><span class="line">36</span><br><span class="line">37</span><br><span class="line">38</span><br><span class="line">39</span><br><span class="line">40</span><br><span class="line">41</span><br><span class="line">42</span><br><span class="line">43</span><br><span class="line">44</span><br><span class="line">45</span><br><span class="line">46</span><br><span class="line">47</span><br><span class="line">48</span><br><span class="line">49</span><br><span class="line">50</span><br><span class="line">51</span><br><span class="line">52</span><br><span class="line">53</span><br></pre></td><td class="code"><pre><span class="line"><span class="keyword">with</span> (<span class="keyword">this</span>) &#123;</span><br><span class="line">  <span class="comment">// this 就是 vm</span></span><br><span class="line">  <span class="keyword">return</span> _c(</span><br><span class="line">    <span class="string">'div'</span>,</span><br><span class="line">    &#123;</span><br><span class="line">      attrs: &#123;</span><br><span class="line">        id: <span class="string">'app'</span></span><br><span class="line">      &#125;</span><br><span class="line">    &#125;,</span><br><span class="line">    [</span><br><span class="line">      _c(<span class="string">'div'</span>, [</span><br><span class="line">        _c(<span class="string">'input'</span>, &#123;</span><br><span class="line">          directives: [</span><br><span class="line">            &#123;</span><br><span class="line">              name: <span class="string">'model'</span>,</span><br><span class="line">              rawName: <span class="string">'v-model'</span>,</span><br><span class="line">              value: title,</span><br><span class="line">              expression: <span class="string">'title'</span></span><br><span class="line">            &#125;</span><br><span class="line">          ],</span><br><span class="line">          domProps: &#123;</span><br><span class="line">            value: title</span><br><span class="line">          &#125;,</span><br><span class="line">          on: &#123;</span><br><span class="line">            input: <span class="function"><span class="keyword">function</span>(<span class="params">$event</span>) </span>&#123;</span><br><span class="line">              <span class="keyword">if</span> ($event.target.composing) <span class="keyword">return</span></span><br><span class="line">              title = $event.target.value</span><br><span class="line">            &#125;</span><br><span class="line">          &#125;</span><br><span class="line">        &#125;),</span><br><span class="line">        _v(<span class="string">' '</span>),</span><br><span class="line">        _c(</span><br><span class="line">          <span class="string">'button'</span>,</span><br><span class="line">          &#123;</span><br><span class="line">            on: &#123;</span><br><span class="line">              click: add</span><br><span class="line">            &#125;</span><br><span class="line">          &#125;,</span><br><span class="line">          [_v(<span class="string">'submit'</span>)]</span><br><span class="line">        )</span><br><span class="line">      ]),</span><br><span class="line">      _v(<span class="string">' '</span>),</span><br><span class="line">      _c(<span class="string">'div'</span>, [</span><br><span class="line">        _c(</span><br><span class="line">          <span class="string">'ul'</span>,</span><br><span class="line">          _l(list, <span class="function"><span class="keyword">function</span>(<span class="params">item</span>) </span>&#123;</span><br><span class="line">            <span class="keyword">return</span> _c(<span class="string">'li'</span>, [_v(_s(item))])</span><br><span class="line">          &#125;)</span><br><span class="line">        )</span><br><span class="line">      ])</span><br><span class="line">    ]</span><br><span class="line">  )</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<ul>
<li>根据 todo-list demo 的 render 函数：<ul>
<li>v-model 是怎么实现的？<ul>
<li>一个 get 一个 set</li>
</ul>
</li>
<li>v-on:click 怎么实现？<ul>
<li>渲染 button 的时候绑定上 click 事件，定义 add 函数</li>
</ul>
</li>
<li>v-for 怎么实现的？<ul>
<li>list 数组遍历，每个元素封装成 li 标签汇成一个数组，一起返回作为 ul 标签的子元素</li>
</ul>
</li>
</ul>
</li>
</ul>
<h3 id="1-5-3-render-函数与-vdom"><a href="#1-5-3-render-函数与-vdom" class="headerlink" title="1.5.3. render 函数与 vdom"></a>1.5.3. render 函数与 vdom</h3><figure class="highlight js"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br><span class="line">15</span><br><span class="line">16</span><br><span class="line">17</span><br></pre></td><td class="code"><pre><span class="line"><span class="comment">// render函数</span></span><br><span class="line"><span class="keyword">with</span> (<span class="keyword">this</span>) &#123;</span><br><span class="line">  <span class="keyword">return</span> _c(</span><br><span class="line">    <span class="string">'div'</span>,</span><br><span class="line">    &#123;</span><br><span class="line">      attrs: &#123; <span class="attr">id</span>: <span class="string">'app'</span> &#125;</span><br><span class="line">    &#125;,</span><br><span class="line">    [_c(<span class="string">'p'</span>, [_v(_s(price))])]</span><br><span class="line">  )</span><br><span class="line">&#125;</span><br><span class="line"></span><br><span class="line"><span class="comment">// snabbdom中的h函数</span></span><br><span class="line"><span class="keyword">var</span> vnode = h(<span class="string">'div#container.two.classer'</span>, &#123; <span class="attr">on</span>: &#123; <span class="attr">click</span>: someFn &#125; &#125;, [</span><br><span class="line">  h(<span class="string">'span'</span>, &#123; <span class="attr">style</span>: &#123; <span class="attr">fontWeight</span>: <span class="string">'bold'</span> &#125; &#125;, <span class="string">'This is bold'</span>),</span><br><span class="line">  <span class="string">'and this is just normal text'</span>,</span><br><span class="line">  h(<span class="string">'a'</span>, &#123; <span class="attr">props</span>: &#123; <span class="attr">href</span>: <span class="string">'/foo'</span> &#125; &#125;, <span class="string">"I'll take you places!"</span>)</span><br><span class="line">])</span><br></pre></td></tr></table></figure>
<ul>
<li>vm._c 其实就相当于 snabbdom 中的 h 函数</li>
<li>render 函数执行之后，返回的是 vnode</li>
</ul>
<figure class="highlight js"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line">vm._update(vnode) &#123;</span><br><span class="line">  <span class="keyword">const</span> prevVnode = vm._vnode</span><br><span class="line">  vm._vnode = vnode</span><br><span class="line">  <span class="keyword">if</span> (!prevVnode) &#123;</span><br><span class="line">    vm.$el = vm.__patch__(vm.$el, vnode)</span><br><span class="line">  &#125; <span class="keyword">else</span> &#123;</span><br><span class="line">    vm.$el = vm.__patch__(prevVnode, vnode)</span><br><span class="line">  &#125;</span><br><span class="line">&#125;</span><br><span class="line"></span><br><span class="line"><span class="function"><span class="keyword">function</span> <span class="title">updateComponent</span>(<span class="params"></span>) </span>&#123;</span><br><span class="line">  <span class="comment">// vm._redner即上面的render函数，返回vnode</span></span><br><span class="line">  vm._update(vm._render())</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<ul>
<li>updateComponent 中实现了 vdom 中的 patch</li>
<li>页面首次渲染执行 updateComponent</li>
<li>data 中每次修改属性,执行 updateComponent</li>
</ul>
<h3 id="1-5-4-问题解答"><a href="#1-5-4-问题解答" class="headerlink" title="1.5.4. 问题解答"></a>1.5.4. 问题解答</h3><ul>
<li>模板：本质字符串，有逻辑，嵌入 JS 变量</li>
<li>模板必须转换为 JS 代码</li>
<li>render 函数</li>
<li>render 函数执行是返回 vnode</li>
<li>updateComponent</li>
</ul>
<h2 id="1-6-vue-的整个实现流程"><a href="#1-6-vue-的整个实现流程" class="headerlink" title="1.6. vue 的整个实现流程"></a>1.6. vue 的整个实现流程</h2><blockquote>
<p>vue 整个的实现流程是怎么样的？</p>
</blockquote>
<h3 id="1-6-1-第一步：解析模板成-render-函数"><a href="#1-6-1-第一步：解析模板成-render-函数" class="headerlink" title="1.6.1. 第一步：解析模板成 render 函数"></a>1.6.1. 第一步：解析模板成 render 函数</h3><ul>
<li>with 的用法</li>
<li>模板中的所有信息都被 render 函数包含</li>
<li>模板中用到的 data 中的属性，都变成了 JS 变量</li>
<li>模板中的 v-model v-for v-on 都变成了 JS 逻辑</li>
<li>render 函数返回 vnode</li>
</ul>
<figure class="highlight js"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br></pre></td><td class="code"><pre><span class="line">&lt;div id=<span class="string">"app"</span>&gt;</span><br><span class="line">  &lt;div&gt;</span><br><span class="line">    &lt;input v-model=<span class="string">"title"</span> /&gt; <span class="xml"><span class="tag">&lt;<span class="name">button</span> <span class="attr">v-on:click</span>=<span class="string">"add"</span>&gt;</span>submit<span class="tag">&lt;/<span class="name">button</span>&gt;</span></span></span><br><span class="line">  &lt;<span class="regexp">/div&gt;</span></span><br><span class="line"><span class="regexp">  &lt;div&gt;</span></span><br><span class="line"><span class="regexp">    &lt;ul&gt;</span></span><br><span class="line"><span class="regexp">      &lt;li v-for="item in list"&gt;&#123;&#123; item &#125;&#125;&lt;/</span>li&gt;</span><br><span class="line">    &lt;<span class="regexp">/ul&gt;</span></span><br><span class="line"><span class="regexp">  &lt;/</span>div&gt;</span><br><span class="line">&lt;<span class="regexp">/div&gt;</span></span><br></pre></td></tr></table></figure>
<h3 id="1-6-2-第二步：响应式开始监听"><a href="#1-6-2-第二步：响应式开始监听" class="headerlink" title="1.6.2. 第二步：响应式开始监听"></a>1.6.2. 第二步：响应式开始监听</h3><ul>
<li>Object.defineProperty</li>
<li>将 data 的属性代理到了 vm 上</li>
</ul>
<h3 id="1-6-3-第三步：首次渲染，显示页面，绑定依赖"><a href="#1-6-3-第三步：首次渲染，显示页面，绑定依赖" class="headerlink" title="1.6.3. 第三步：首次渲染，显示页面，绑定依赖"></a>1.6.3. 第三步：首次渲染，显示页面，绑定依赖</h3><ul>
<li>初次渲染，执行 updateComponent，执行 vm._render()</li>
<li>执行 render()函数，会访问到 vm.list 和 vm.title</li>
<li>会被响应式的 get 方法监听到</li>
<li>执行 updateComponent，会走到 vdom 的 patch 方法</li>
<li>patch 将 vnode 渲染成 DOM，初次渲染完成</li>
</ul>
<figure class="highlight js"><table><tr><td class="gutter"><pre><span class="line">1</span><br><span class="line">2</span><br><span class="line">3</span><br><span class="line">4</span><br><span class="line">5</span><br><span class="line">6</span><br><span class="line">7</span><br><span class="line">8</span><br><span class="line">9</span><br><span class="line">10</span><br><span class="line">11</span><br><span class="line">12</span><br><span class="line">13</span><br><span class="line">14</span><br></pre></td><td class="code"><pre><span class="line">vm._update(vnode) &#123;</span><br><span class="line">  <span class="keyword">const</span> prevVnode = vm._vnode</span><br><span class="line">  vm._vnode = vnode</span><br><span class="line">  <span class="keyword">if</span> (!prevVnode) &#123;</span><br><span class="line">    vm.$el = vm.__patch__(vm.$el, vnode)</span><br><span class="line">  &#125; <span class="keyword">else</span> &#123;</span><br><span class="line">    vm.$el = vm.__patch__(prevVnode, vnode)</span><br><span class="line">  &#125;</span><br><span class="line">&#125;</span><br><span class="line"></span><br><span class="line"><span class="function"><span class="keyword">function</span> <span class="title">updateComponent</span>(<span class="params"></span>) </span>&#123;</span><br><span class="line">  <span class="comment">// vm._redner即上面的render函数，返回vnode</span></span><br><span class="line">  vm._update(vm._render())</span><br><span class="line">&#125;</span><br></pre></td></tr></table></figure>
<blockquote>
<p>为什么要监听 get，直接监听 set 不行吗？</p>
</blockquote>
<ul>
<li>data 中有很多属性，有些被用到，有些可能不被用到</li>
<li>被用到的会走到 get，不被用到的不会走到 get</li>
<li>未走到 get 中的属性，set 的时候我们也无需关心</li>
<li>避免不必要的重复渲染</li>
</ul>
<h3 id="1-6-4-第四步：data-属性变化，触发-rerender-函数"><a href="#1-6-4-第四步：data-属性变化，触发-rerender-函数" class="headerlink" title="1.6.4. 第四步：data 属性变化，触发 rerender 函数"></a>1.6.4. 第四步：data 属性变化，触发 rerender 函数</h3><ul>
<li>修改属性，被响应式的 set 监听到</li>
<li>set 中执行 updateComponent</li>
<li>updateComponent 重新执行 vm._render()</li>
<li>生成 vnode 和 prevVnode，通过 patch 进行对比</li>
<li>渲染到 HTML 中</li>
</ul>
<h3 id="1-6-5-问题解答"><a href="#1-6-5-问题解答" class="headerlink" title="1.6.5. 问题解答"></a>1.6.5. 问题解答</h3><ul>
<li>第一步：解析模板成 render 函数</li>
<li>第二步：响应式开始监听</li>
<li>第三步：首次渲染，显示页面，绑定依赖</li>
<li>第四步：data 属性变化，触发 rerender 函数</li>
</ul>
<h2 id="1-7-总结"><a href="#1-7-总结" class="headerlink" title="1.7. 总结"></a>1.7. 总结</h2><ol>
<li><p>说一下使用 jQuery 和使用框架的区别</p>
<ul>
<li>数据和视图的分离，解耦</li>
<li>以数据驱动视图，只关心数据变化，DOM 操作被封装</li>
</ul>
</li>
<li><p>什么是 MVVM</p>
<ul>
<li>MVVM ：Model View VIewModel</li>
<li>三者之间的联系，以及如何对应到各段代码</li>
<li>ViewModel 的理解，联系 View 和 Model</li>
</ul>
</li>
<li><p>MVVM 的三要素</p>
<ul>
<li>响应式：vue 如何监听到 data 的每个属性变化？</li>
<li>模板引擎：vue 的模板如何被解析，指令如何处理？</li>
<li>渲染：vue 的模板如何被渲染成 html？以及渲染过程</li>
</ul>
</li>
<li><p>Vue 如何实现响应式</p>
<ul>
<li>关键是理解 Object.defineProperty</li>
<li>将 data 的属性代理到 vm 上</li>
</ul>
</li>
<li><p>vue 如何解析模板</p>
<ul>
<li>模板：本质字符串，有逻辑，嵌入 JS 变量</li>
<li>模板必须转换为 JS 代码（图灵完备语言，有逻辑、渲染 html、JS 变量）</li>
<li>render 函数是什么样子的</li>
<li>render 函数执行是返回 vnode</li>
<li>updateComponent</li>
</ul>
</li>
<li><p>vue 实现的整体流程</p>
<ul>
<li>第一步：解析模板成 render 函数</li>
<li>第二步：响应式开始监听</li>
<li>第三步：首次渲染，显示页面，绑定依赖</li>
<li>第四步：data 属性变化，触发 rerender 函数</li>
</ul>
</li>
</ol>

      
    </div>
    
    
    

    <div>
      
        <div>
    
        <div style="text-align:center;color: #ccc;font-size:14px;">-------------本文结束<i class="fa fa-paw"></i>感谢您的阅读-------------</div>
    
</div>

      
    </div>

    <div>
          
            


          
    </div>

    

    

    

    <footer class="post-footer">
      

      
      
        <div class="post-widgets">
        

        

        
          
          <div id="needsharebutton-postbottom">
            <span class="btn">
              <i class="fa fa-share-alt" aria-hidden="true"></i>
            </span>
          </div>
        
        </div>
      
      

      
        <div class="post-nav">
          <div class="post-nav-next post-nav-item">
            
              <a href="/uncategorized/imooc-frontend-interview/JavaScript高级面试/4. 虚拟DOM.html/" rel="next" title="">
                <i class="fa fa-chevron-left"></i> 
              </a>
            
          </div>

          <span class="post-nav-divider"></span>

          <div class="post-nav-prev post-nav-item">
            
              <a href="/uncategorized/imooc-frontend-interview/JavaScript高级面试/6. hybrid.html/" rel="prev" title="">
                 <i class="fa fa-chevron-right"></i>
              </a>
            
          </div>
        </div>
      

      
      
    </footer>
  </div>
  
  
  
  </article>



    <div class="post-spread">
      
    </div>
  </div>


          </div>
          


          

  
    <div class="comments" id="comments">
      <div id="disqus_thread">
        <noscript>
          Please enable JavaScript to view the
          <a href="https://disqus.com/?ref_noscript">comments powered by Disqus.</a>
        </noscript>
      </div>
    </div>

  



        </div>
        
          
  
  <div class="sidebar-toggle">
    <div class="sidebar-toggle-line-wrap">
      <span class="sidebar-toggle-line sidebar-toggle-line-first"></span>
      <span class="sidebar-toggle-line sidebar-toggle-line-middle"></span>
      <span class="sidebar-toggle-line sidebar-toggle-line-last"></span>
    </div>
  </div>

  <aside id="sidebar" class="sidebar">
    
    <div class="sidebar-inner">

      

      
        <ul class="sidebar-nav motion-element">
          <li class="sidebar-nav-toc sidebar-nav-active" data-target="post-toc-wrap">
            文章目录
          </li>
          <li class="sidebar-nav-overview" data-target="site-overview-wrap">
            站点概览
          </li>
        </ul>
      

      <section class="site-overview-wrap sidebar-panel">
        <div class="site-overview">
          <div class="site-author motion-element" itemprop="author" itemscope="" itemtype="http://schema.org/Person">
            
              <img class="site-author-image" itemprop="image" src="/images/head.jpg" alt="Yomi">
            
              <p class="site-author-name" itemprop="name">Yomi</p>
              <p class="site-description motion-element" itemprop="description">--悟已往之不谏，知来者之可追--</p>
          </div>

          <nav class="site-state motion-element">

            
              <div class="site-state-item site-state-posts">
              
                <a href="/archives/">
              
                  <span class="site-state-item-count">28</span>
                  <span class="site-state-item-name">日志</span>
                </a>
              </div>
            

            
              
              
              <div class="site-state-item site-state-categories">
                <a href="/categories/index.html">
                  <span class="site-state-item-count">6</span>
                  <span class="site-state-item-name">分类</span>
                </a>
              </div>
            

            
              
              
              <div class="site-state-item site-state-tags">
                <a href="/tags/index.html">
                  <span class="site-state-item-count">5</span>
                  <span class="site-state-item-name">标签</span>
                </a>
              </div>
            

          </nav>

          

          
            <div class="links-of-author motion-element">
                
                  <span class="links-of-author-item">
                    <a href="https://github.com/Jem826" target="_blank" title="GitHub">
                      
                        <i class="fa fa-fw fa-github"></i>GitHub</a>
                  </span>
                
                  <span class="links-of-author-item">
                    <a href="https://www.jianshu.com" target="_blank" title="简书">
                      
                        <i class="fa fa-fw fa-heartbeat"></i>简书</a>
                  </span>
                
                  <span class="links-of-author-item">
                    <a href="https://juejin.im" target="_blank" title="掘金">
                      
                        <i class="fa fa-fw fa-gg-circle"></i>掘金</a>
                  </span>
                
                  <span class="links-of-author-item">
                    <a href="tencent://message/?uin=964325846&Site=个人QQ&Menu=yes" target="_blank" title="QQ">
                      
                        <i class="fa fa-fw fa-qq"></i>QQ</a>
                  </span>
                
            </div>
          

          
          

          
          
            <div class="links-of-blogroll motion-element links-of-blogroll-block">
              <div class="links-of-blogroll-title">
                <i class="fa  fa-fw fa-link"></i>
                推荐阅读
              </div>
              <ul class="links-of-blogroll-list">
                
                  <li class="links-of-blogroll-item">
                    <a href="http://www.uisdc.com/" title="优设" target="_blank">优设</a>
                  </li>
                
                  <li class="links-of-blogroll-item">
                    <a href="http://www.zhangxinxu.com/" title="张鑫旭" target="_blank">张鑫旭</a>
                  </li>
                
                  <li class="links-of-blogroll-item">
                    <a href="http://www.alloyteam.com/nav/" title="Web前端导航" target="_blank">Web前端导航</a>
                  </li>
                
                  <li class="links-of-blogroll-item">
                    <a href="http://www.36zhen.com/t?id=3448" title="前端书籍资料" target="_blank">前端书籍资料</a>
                  </li>
                
                  <li class="links-of-blogroll-item">
                    <a href="http://hao.shejidaren.com" title="设计导航" target="_blank">设计导航</a>
                  </li>
                
                  <li class="links-of-blogroll-item">
                    <a href="http://www.vipsheji.cn" title="设计网站大全" target="_blank">设计网站大全</a>
                  </li>
                
                  <li class="links-of-blogroll-item">
                    <a href="http://ife.baidu.com/" title="百度前端技术学院" target="_blank">百度前端技术学院</a>
                  </li>
                
                  <li class="links-of-blogroll-item">
                    <a href="http://wf.uisdc.com/cn/" title="google前端开发基础" target="_blank">google前端开发基础</a>
                  </li>
                
              </ul>
            </div>
          

          

        </div>
      </section>

      
      <!--noindex-->
        <section class="post-toc-wrap motion-element sidebar-panel sidebar-panel-active">
          <div class="post-toc">

            
              
            

            
              <div class="post-toc-content"><ol class="nav"><li class="nav-item nav-level-1"><a class="nav-link" href="#1-MVVM-和-Vue"><span class="nav-text">1. MVVM 和 Vue</span></a><ol class="nav-child"><li class="nav-item nav-level-2"><a class="nav-link" href="#1-1-说一下使用-jQuery-和使用框架的区别"><span class="nav-text">1.1. 说一下使用 jQuery 和使用框架的区别</span></a><ol class="nav-child"><li class="nav-item nav-level-3"><a class="nav-link" href="#1-1-1-jQuery-实现-todo-list"><span class="nav-text">1.1.1. jQuery 实现 todo-list</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-1-2-vue-实现-todo-list"><span class="nav-text">1.1.2. vue 实现 todo-list</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-1-3-jQuery-和框架的区别"><span class="nav-text">1.1.3. jQuery 和框架的区别</span></a></li></ol></li><li class="nav-item nav-level-2"><a class="nav-link" href="#1-2-说一下对-MVVM-的理解"><span class="nav-text">1.2. 说一下对 MVVM 的理解</span></a></li><li class="nav-item nav-level-2"><a class="nav-link" href="#1-3-MVVM-框架的三大要素"><span class="nav-text">1.3. MVVM 框架的三大要素</span></a></li><li class="nav-item nav-level-2"><a class="nav-link" href="#1-4-vue-如何实现响应式"><span class="nav-text">1.4. vue 如何实现响应式</span></a><ol class="nav-child"><li class="nav-item nav-level-3"><a class="nav-link" href="#1-4-1-什么是响应式"><span class="nav-text">1.4.1. 什么是响应式</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-4-2-Object-defineProperty"><span class="nav-text">1.4.2. Object.defineProperty</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-4-3-模拟"><span class="nav-text">1.4.3. 模拟</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-4-4-问题解答"><span class="nav-text">1.4.4. 问题解答</span></a></li></ol></li><li class="nav-item nav-level-2"><a class="nav-link" href="#1-5-vue-如何解析模板"><span class="nav-text">1.5. vue 如何解析模板</span></a><ol class="nav-child"><li class="nav-item nav-level-3"><a class="nav-link" href="#1-5-1-模板是什么"><span class="nav-text">1.5.1. 模板是什么</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-5-2-render-函数"><span class="nav-text">1.5.2. render 函数</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-5-3-render-函数与-vdom"><span class="nav-text">1.5.3. render 函数与 vdom</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-5-4-问题解答"><span class="nav-text">1.5.4. 问题解答</span></a></li></ol></li><li class="nav-item nav-level-2"><a class="nav-link" href="#1-6-vue-的整个实现流程"><span class="nav-text">1.6. vue 的整个实现流程</span></a><ol class="nav-child"><li class="nav-item nav-level-3"><a class="nav-link" href="#1-6-1-第一步：解析模板成-render-函数"><span class="nav-text">1.6.1. 第一步：解析模板成 render 函数</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-6-2-第二步：响应式开始监听"><span class="nav-text">1.6.2. 第二步：响应式开始监听</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-6-3-第三步：首次渲染，显示页面，绑定依赖"><span class="nav-text">1.6.3. 第三步：首次渲染，显示页面，绑定依赖</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-6-4-第四步：data-属性变化，触发-rerender-函数"><span class="nav-text">1.6.4. 第四步：data 属性变化，触发 rerender 函数</span></a></li><li class="nav-item nav-level-3"><a class="nav-link" href="#1-6-5-问题解答"><span class="nav-text">1.6.5. 问题解答</span></a></li></ol></li><li class="nav-item nav-level-2"><a class="nav-link" href="#1-7-总结"><span class="nav-text">1.7. 总结</span></a></li></ol></li></ol></div>
            

          </div>
        </section>
      <!--/noindex-->
      

      
        <div class="back-to-top">
          <i class="fa fa-arrow-up"></i>
          
            <span id="scrollpercent"><span>0</span>%</span>
          
        </div>
      

    </div>
  </aside>


        
      </div>
    </main>

    <footer id="footer" class="footer">
      <div class="footer-inner">
        <div class="copyright">&copy; <span itemprop="copyrightYear">2019</span>
  <span class="with-love">
    <i class="fa fa-user"></i>
  </span>
  <span class="author" itemprop="copyrightHolder">Yomi</span>

  
</div>

<!--

  <div class="powered-by">由 <a class="theme-link" target="_blank" href="https://hexo.io">Hexo</a> 强力驱动</div>




  <span class="post-meta-divider">|</span>



  <div class="theme-info">主题 &mdash; <a class="theme-link" target="_blank" href="https://github.com/iissnan/hexo-theme-next">NexT.Pisces</a> v5.1.4</div>



-->

        
<div class="busuanzi-count">
  <script async src="https://busuanzi.ibruce.info/busuanzi/2.3/busuanzi.pure.mini.js"></script>

  
    <span class="site-uv">
      <i class="fa fa-user"></i> 访问人数
      <span class="busuanzi-value" id="busuanzi_value_site_uv"></span>
      
    </span>
  

  
    <span class="site-pv">
      <i class="fa fa-eye"></i> 总访问量
      <span class="busuanzi-value" id="busuanzi_value_site_pv"></span>
      
    </span>
  
</div>








        
      </div>
    </footer>

    

    

  </div>

  

<script type="text/javascript">
  if (Object.prototype.toString.call(window.Promise) !== '[object Function]') {
    window.Promise = null;
  }
</script>









  












  
  
    <script type="text/javascript" src="/lib/jquery/index.js?v=2.1.3"></script>
  

  
  
    <script type="text/javascript" src="/lib/fastclick/lib/fastclick.min.js?v=1.0.6"></script>
  

  
  
    <script type="text/javascript" src="/lib/jquery_lazyload/jquery.lazyload.js?v=1.9.7"></script>
  

  
  
    <script type="text/javascript" src="/lib/velocity/velocity.min.js?v=1.2.1"></script>
  

  
  
    <script type="text/javascript" src="/lib/velocity/velocity.ui.min.js?v=1.2.1"></script>
  

  
  
    <script type="text/javascript" src="/lib/fancybox/source/jquery.fancybox.pack.js?v=2.1.5"></script>
  


  


  <script type="text/javascript" src="/js/src/utils.js?v=5.1.4"></script>

  <script type="text/javascript" src="/js/src/motion.js?v=5.1.4"></script>



  
  


  <script type="text/javascript" src="/js/src/affix.js?v=5.1.4"></script>

  <script type="text/javascript" src="/js/src/schemes/pisces.js?v=5.1.4"></script>



  
  <script type="text/javascript" src="/js/src/scrollspy.js?v=5.1.4"></script>
<script type="text/javascript" src="/js/src/post-details.js?v=5.1.4"></script>



  


  <script type="text/javascript" src="/js/src/bootstrap.js?v=5.1.4"></script>



  


  

    
      <script id="dsq-count-scr" src="https://true.disqus.com/count.js" async></script>
    

    
      <script type="text/javascript">
        var disqus_config = function () {
          this.page.url = 'https://xczhello.gitee.io/uncategorized/imooc-frontend-interview/JavaScript高级面试/5. MVVM和Vue.html/';
          this.page.identifier = 'uncategorized/imooc-frontend-interview/JavaScript高级面试/5. MVVM和Vue.html/';
          this.page.title = '';
        };
        var d = document, s = d.createElement('script');
        s.src = 'https://true.disqus.com/embed.js';
        s.setAttribute('data-timestamp', '' + +new Date());
        (d.head || d.body).appendChild(s);
      </script>
    

  




	





  














  

  <script type="text/javascript">
    // Popup Window;
    var isfetched = false;
    var isXml = true;
    // Search DB path;
    var search_path = "search.xml";
    if (search_path.length === 0) {
      search_path = "search.xml";
    } else if (/json$/i.test(search_path)) {
      isXml = false;
    }
    var path = "/" + search_path;
    // monitor main search box;

    var onPopupClose = function (e) {
      $('.popup').hide();
      $('#local-search-input').val('');
      $('.search-result-list').remove();
      $('#no-result').remove();
      $(".local-search-pop-overlay").remove();
      $('body').css('overflow', '');
    }

    function proceedsearch() {
      $("body")
        .append('<div class="search-popup-overlay local-search-pop-overlay"></div>')
        .css('overflow', 'hidden');
      $('.search-popup-overlay').click(onPopupClose);
      $('.popup').toggle();
      var $localSearchInput = $('#local-search-input');
      $localSearchInput.attr("autocapitalize", "none");
      $localSearchInput.attr("autocorrect", "off");
      $localSearchInput.focus();
    }

    // search function;
    var searchFunc = function(path, search_id, content_id) {
      'use strict';

      // start loading animation
      $("body")
        .append('<div class="search-popup-overlay local-search-pop-overlay">' +
          '<div id="search-loading-icon">' +
          '<i class="fa fa-spinner fa-pulse fa-5x fa-fw"></i>' +
          '</div>' +
          '</div>')
        .css('overflow', 'hidden');
      $("#search-loading-icon").css('margin', '20% auto 0 auto').css('text-align', 'center');

      $.ajax({
        url: path,
        dataType: isXml ? "xml" : "json",
        async: true,
        success: function(res) {
          // get the contents from search data
          isfetched = true;
          $('.popup').detach().appendTo('.header-inner');
          var datas = isXml ? $("entry", res).map(function() {
            return {
              title: $("title", this).text(),
              content: $("content",this).text(),
              url: $("url" , this).text()
            };
          }).get() : res;
          var input = document.getElementById(search_id);
          var resultContent = document.getElementById(content_id);
          var inputEventFunction = function() {
            var searchText = input.value.trim().toLowerCase();
            var keywords = searchText.split(/[\s\-]+/);
            if (keywords.length > 1) {
              keywords.push(searchText);
            }
            var resultItems = [];
            if (searchText.length > 0) {
              // perform local searching
              datas.forEach(function(data) {
                var isMatch = false;
                var hitCount = 0;
                var searchTextCount = 0;
                var title = data.title.trim();
                var titleInLowerCase = title.toLowerCase();
                var content = data.content.trim().replace(/<[^>]+>/g,"");
                var contentInLowerCase = content.toLowerCase();
                var articleUrl = decodeURIComponent(data.url);
                var indexOfTitle = [];
                var indexOfContent = [];
                // only match articles with not empty titles
                if(title != '') {
                  keywords.forEach(function(keyword) {
                    function getIndexByWord(word, text, caseSensitive) {
                      var wordLen = word.length;
                      if (wordLen === 0) {
                        return [];
                      }
                      var startPosition = 0, position = [], index = [];
                      if (!caseSensitive) {
                        text = text.toLowerCase();
                        word = word.toLowerCase();
                      }
                      while ((position = text.indexOf(word, startPosition)) > -1) {
                        index.push({position: position, word: word});
                        startPosition = position + wordLen;
                      }
                      return index;
                    }

                    indexOfTitle = indexOfTitle.concat(getIndexByWord(keyword, titleInLowerCase, false));
                    indexOfContent = indexOfContent.concat(getIndexByWord(keyword, contentInLowerCase, false));
                  });
                  if (indexOfTitle.length > 0 || indexOfContent.length > 0) {
                    isMatch = true;
                    hitCount = indexOfTitle.length + indexOfContent.length;
                  }
                }

                // show search results

                if (isMatch) {
                  // sort index by position of keyword

                  [indexOfTitle, indexOfContent].forEach(function (index) {
                    index.sort(function (itemLeft, itemRight) {
                      if (itemRight.position !== itemLeft.position) {
                        return itemRight.position - itemLeft.position;
                      } else {
                        return itemLeft.word.length - itemRight.word.length;
                      }
                    });
                  });

                  // merge hits into slices

                  function mergeIntoSlice(text, start, end, index) {
                    var item = index[index.length - 1];
                    var position = item.position;
                    var word = item.word;
                    var hits = [];
                    var searchTextCountInSlice = 0;
                    while (position + word.length <= end && index.length != 0) {
                      if (word === searchText) {
                        searchTextCountInSlice++;
                      }
                      hits.push({position: position, length: word.length});
                      var wordEnd = position + word.length;

                      // move to next position of hit

                      index.pop();
                      while (index.length != 0) {
                        item = index[index.length - 1];
                        position = item.position;
                        word = item.word;
                        if (wordEnd > position) {
                          index.pop();
                        } else {
                          break;
                        }
                      }
                    }
                    searchTextCount += searchTextCountInSlice;
                    return {
                      hits: hits,
                      start: start,
                      end: end,
                      searchTextCount: searchTextCountInSlice
                    };
                  }

                  var slicesOfTitle = [];
                  if (indexOfTitle.length != 0) {
                    slicesOfTitle.push(mergeIntoSlice(title, 0, title.length, indexOfTitle));
                  }

                  var slicesOfContent = [];
                  while (indexOfContent.length != 0) {
                    var item = indexOfContent[indexOfContent.length - 1];
                    var position = item.position;
                    var word = item.word;
                    // cut out 100 characters
                    var start = position - 20;
                    var end = position + 80;
                    if(start < 0){
                      start = 0;
                    }
                    if (end < position + word.length) {
                      end = position + word.length;
                    }
                    if(end > content.length){
                      end = content.length;
                    }
                    slicesOfContent.push(mergeIntoSlice(content, start, end, indexOfContent));
                  }

                  // sort slices in content by search text's count and hits' count

                  slicesOfContent.sort(function (sliceLeft, sliceRight) {
                    if (sliceLeft.searchTextCount !== sliceRight.searchTextCount) {
                      return sliceRight.searchTextCount - sliceLeft.searchTextCount;
                    } else if (sliceLeft.hits.length !== sliceRight.hits.length) {
                      return sliceRight.hits.length - sliceLeft.hits.length;
                    } else {
                      return sliceLeft.start - sliceRight.start;
                    }
                  });

                  // select top N slices in content

                  var upperBound = parseInt('1');
                  if (upperBound >= 0) {
                    slicesOfContent = slicesOfContent.slice(0, upperBound);
                  }

                  // highlight title and content

                  function highlightKeyword(text, slice) {
                    var result = '';
                    var prevEnd = slice.start;
                    slice.hits.forEach(function (hit) {
                      result += text.substring(prevEnd, hit.position);
                      var end = hit.position + hit.length;
                      result += '<b class="search-keyword">' + text.substring(hit.position, end) + '</b>';
                      prevEnd = end;
                    });
                    result += text.substring(prevEnd, slice.end);
                    return result;
                  }

                  var resultItem = '';

                  if (slicesOfTitle.length != 0) {
                    resultItem += "<li><a href='" + articleUrl + "' class='search-result-title'>" + highlightKeyword(title, slicesOfTitle[0]) + "</a>";
                  } else {
                    resultItem += "<li><a href='" + articleUrl + "' class='search-result-title'>" + title + "</a>";
                  }

                  slicesOfContent.forEach(function (slice) {
                    resultItem += "<a href='" + articleUrl + "'>" +
                      "<p class=\"search-result\">" + highlightKeyword(content, slice) +
                      "...</p>" + "</a>";
                  });

                  resultItem += "</li>";
                  resultItems.push({
                    item: resultItem,
                    searchTextCount: searchTextCount,
                    hitCount: hitCount,
                    id: resultItems.length
                  });
                }
              })
            };
            if (keywords.length === 1 && keywords[0] === "") {
              resultContent.innerHTML = '<div id="no-result"><i class="fa fa-search fa-5x" /></div>'
            } else if (resultItems.length === 0) {
              resultContent.innerHTML = '<div id="no-result"><i class="fa fa-frown-o fa-5x" /></div>'
            } else {
              resultItems.sort(function (resultLeft, resultRight) {
                if (resultLeft.searchTextCount !== resultRight.searchTextCount) {
                  return resultRight.searchTextCount - resultLeft.searchTextCount;
                } else if (resultLeft.hitCount !== resultRight.hitCount) {
                  return resultRight.hitCount - resultLeft.hitCount;
                } else {
                  return resultRight.id - resultLeft.id;
                }
              });
              var searchResultList = '<ul class=\"search-result-list\">';
              resultItems.forEach(function (result) {
                searchResultList += result.item;
              })
              searchResultList += "</ul>";
              resultContent.innerHTML = searchResultList;
            }
          }

          if ('auto' === 'auto') {
            input.addEventListener('input', inputEventFunction);
          } else {
            $('.search-icon').click(inputEventFunction);
            input.addEventListener('keypress', function (event) {
              if (event.keyCode === 13) {
                inputEventFunction();
              }
            });
          }

          // remove loading animation
          $(".local-search-pop-overlay").remove();
          $('body').css('overflow', '');

          proceedsearch();
        }
      });
    }

    // handle and trigger popup window;
    $('.popup-trigger').click(function(e) {
      e.stopPropagation();
      if (isfetched === false) {
        searchFunc(path, 'local-search-input', 'local-search-result');
      } else {
        proceedsearch();
      };
    });

    $('.popup-btn-close').click(onPopupClose);
    $('.popup').click(function(e){
      e.stopPropagation();
    });
    $(document).on('keyup', function (event) {
      var shouldDismissSearchPopup = event.which === 27 &&
        $('.search-popup').is(':visible');
      if (shouldDismissSearchPopup) {
        onPopupClose();
      }
    });
  </script>





  

  

  

  
  
  
  <link rel="stylesheet" href="/lib/needsharebutton/needsharebutton.css">

  
  
  <script src="/lib/needsharebutton/needsharebutton.js"></script>

  <script>
    
      pbOptions = {};
      
          pbOptions.iconStyle = "box";
      
          pbOptions.boxForm = "horizontal";
      
          pbOptions.position = "bottomCenter";
      
          pbOptions.networks = "Weibo,Wechat,Douban,QQZone,Twitter,Facebook,GooglePlus,Linkedin,Evernote";
      
      new needShareButton('#needsharebutton-postbottom', pbOptions);
    
    
  </script>

  

  

  

  

  <!-- 页面点击小红心 -->
  <script type="text/javascript" src="/js/src/click.js"></script>
  <!-- 背景动画 -->
  <script type="text/javascript" src="/js/src/particle.js"></script>
<script src="/live2dw/lib/L2Dwidget.min.js?0c58a1486de42ac6cc1c59c7d98ae887"></script><script>L2Dwidget.init({"pluginRootPath":"live2dw/","pluginJsPath":"lib/","pluginModelPath":"assets/","tagMode":false,"debug":false,"model":{"jsonPath":"/live2dw/assets/tororo.model.json"},"display":{"position":"right","width":120,"height":240},"mobile":{"show":true},"log":false});</script></body>
</html>
